Genatin subbing compositions containing a mixture of formamide and glycerol-alpha-chlorohydrin



Patented Feb. 8, 1949 Gamers *SU'BBING- COMPOSITIGNS-CON- TAI'NI-N G A MIXTURE OF -FORMAMIDE AND GLYGERQL-w-GHLOROHYDRIN IF'rank I J. Kaszuba Binghamton, N. vYL, Qassignor to "General Anil-inei& Film Corporation, New 'York',N. Y. a" corporation oii'Delaware 'No Drawing. ApplicationQDecenrber 17,1946, Serial N0. 716,880

' This invention relates to the'subbing'of photographic film, and moreparticularly to the preparation of gelatin subbing compositions in which thcgelatin is dispersed therein 'by'means of" a mixture" of iormamideand 'glycerol-oz-chlorohydrin.

lnethe manufacture of; photographic. film, itis necessary to=afilxa photo-sensitive layer to a suitablesupport. Usually,:the support is prepared from. a cellulose derivative, or from. some other flexible thermoplastic:material coated with adiscreet layer of a cellulose derivative. Whatever its -oomposition,-. the' support. is hydrophobic. On the other hand, the colloidal carrier inv thephotosensitive layeris usually some 'hydrophilic substance,.-such as: gelatin. When gelatin is coated on-a film base, it is found that there is little or no adhesion-betweenthe two. :As-a matter of fact, thehydrophilic layer can be peeled from the support withcomplete ease.

-Inorder to: insure adequate adhesion between the two layers, it is necessary to impart a hydrophilic nature to the surface of the film base. Thisisaccomplished by treating thesupport with what is-known tothe. rates a subbing solution." This is merely-an'organosol oiogelatin or some other water sensitive substance. It is believed that the organic solvents in the subbing solution soften the surfaceof the'film base so that thehydrophilic material is -simultaneously deposited in the said'surfa'ce'. Thus; when a subbedi support is coatedwith-a photo-sensitive layer excellent adhesion results between the two.

: Hither-to, gelatin :organosols were prepared according to theiollowingf formula:

s Grams -Ge1atin TIiOO Water 4.00 Acid (acetic acid, and the like as a dispersing medium); 2.00 Methanol "43:00 Acetone 50100 Although excellent adhesion is'obtained by the use-of a subbing solution of this type, it Hequentl-y-gives rise to serious desensitizationof the silver-halide photographic emulsions, especially when these-emulsions-are or the type which are highly-sensitive to-actinic rays.

"=-l?his defectis apparently caused by the acid presentin thetsublayer; yet iiithe acid-is left out.of.-.the.compositiomthe gelatin cannot be dispersed in the organic solvents-in a. suflicient quantity to effect -.suitable-..adhesion-. in the finished film. -Moreover,the-presence .of an -acid has the disadvantage inthat. itvolatilizesduringthesub- 5 Claims. (Cl. 106-135) .loing operation. and corrodes theYfilm-making. ma-

chinery and the solvent recovery. system---.which is customarily .a part. thereof.

'Ihepresent invention has as an object to overcome the. above mentioned. di'fficulty and to pro-- videianiimproved' methodof dispersingg'elatin in.

- is dispersed by means of norl-d'esensi'tizing, ,.non;

corrosive dispersing. agents, whichhave 'no adverse efiect upon photographic gelatino ;s'ilverhalide emulsions- Other objects and advantages will appear hereinaiter.

These objects. are accomplished by thev usepf a mixture of formamideand -glycerol-a-chloro hydrin as the gelatine-dispersing medium- "It has'been found that if the water and organic acid in atypicalfgel'atin subbingcomposition are rep1aced.by the said mixture; excellent dispersions of gelatin are obtained, which serve as suitable subbing compositions, giving satisfactory adhesion"without.desensitizationof the silver-halide emulsion layer during storage andprolonged'iage mg:

During the experimentation which. led to my invention, I found that acetamidacould not "be substitutedifor the formamide due to the fact that theformer is a solid atroom temperature and-its use is impractical. Various dichlorohydrins were also considered as possible substitutes for the glycerol-a-chlorohydrin; but were found to beof "toolliinitedfstability. Glycerol, glycols, ethylene b ing operation. Eormamide withglyceroLonwith aglycol, .was 'found to. .be inoperative. Onathe otherv hand, Whenglyceroh m chlorohydrinis-used.

alone. the gelatin. is dispersed very slowly; since chlorohydrin is: not efiicient as? a dispersingamedium..- in the. presence ganieso1vents.

-of large amounts: ofor The amount of the foregoing mixture, which may be employed as a dispersing agent, may vary over a small range such as, for example, from about 5% to 20% and preferably from 8% to of a 1:1 or 1:2 mixture of formamide and glycerol-a-chlorohydrin, respectively. The gelatin may range from about 0.5% to 1.5% and preferably from 0.5% to 1%. the gelatin is dissolved consists substantially of an organic solvent or a mixture of such solvents. All proportions are by weight.

The subbing compositions are made by mixing the components in various ways in proportions so as to form a free'fiowing composition which dries or sets within a reasonable length of time and forms a thin layer on a film base. In general,

it is desirable to dissolve the gelatin in a 1:1-or

1:2 mixture of formamide and glycerol-a-chlorohydrin, respectively, and add to it the neces sary solvent until the gelatin is completely dispersed therein. Slight warming and agitation will facilitate the dispersion of the gelatin in' the dispersion mixture. The organic solvents such as alcohol, acetone, ethylene dichloride, methyl cellosolve, or other solvents normally employed in subbing compositions, or mixtures thereof, are then mixed with the dispersion of gelatin and the solution thus obtained is coated on the film base in any convenient manner.

It may be pointed out at this point, that the nature of the organic solvent or solvent mixture isimmaterial, so long as it wets or bites into the photographic film support, and the term solvent as used in the claims should be so construed. Since the materials suitable for film base and their solvent properties are known, no difiiculty is presented in selecting a suitable solvent or solvent mixture for use in the subbing compositions.

The application of the subbing solution according to the present invention may be carried out in any manner well-known to those skilled in the art, such as by beading, immersion, roll application, etc. The film base or support may be any cellulose organic derivative composition usually used for this purpose. It may consist of a simple'ester such as cellulose acetate, cellulose triacetate, a mixed ester such as cellulose acetate-propionate, cellulose butyrate, cellulose a'cetate-butyrate, ethers of cellulose, such as the methyl ether, ethyl ether, and the like, or of any film-forming polymer or resin such as polyvinyl chloride, copolymers of polyvinyl chloridevinyl acetate, copolymers of polyvinyl chloride-- solvent or solvent mixture employed must be such that it will have a solvent, or at least a softening or swelling action on the cellulose derivative and the syntheticpolymer support, so as to stick or anchor the gelatin upon the area of the support which has been softened or swollen. For example, with a cellulose acetate or a superpolymer base a low molecular weight alcohol, e. g.. methanol, ethanol, and the like, or a ketone, such as acetone or a mixture of alcohol or acetone, may be employed. The average ratio of alcohol to acetone ranges from about 5050% to '75-25%, respectively. The most practical results, however, may be determined by a few simple experi The phase in which accordance with the present invention, may be applied to one or both sides of a suitable photographic film support.

The method of subbing a photographic film base is conveniently illustrated by the following examples, it being understood that they are illustrative only and should not be construed as limitative of the present invention.

Example I A gelatin solution was made up having the following composition:

Parts Gelatin e 1.0 Formamide 5.0 Glycerol-a-chlorohydrin 10.0 Methanol -e- 42.0. Acetone 42.0

The formamide and glycerol-a-chiorohydrin were added to the gelatin and the mixture stirred until solution was effected. Gentle warming accelerates the process. After mixing thoroughly, it is slowly added to the mixture of acetone and methanol with adequate stirring.

The subbing composition thus obtained is a clear dispersion in which the gelatin is completely dispersed.

A film support of cellulose acetate was led through an immersion type hopper containing the foregoing solution. The support, after leaving the subbing apparatus, was led through an appropriate drying apparatus maintained at a temperature of -200 F., where the solvents were evaporated from the surface of the support.

Example II A film base of cellulose acetate-propionate having an acetyl content of 30% was coated with the following subbing composition:

Parts Gelatin 1.0 Formamide 4.0 Glycerol-a-chlorohydrin 4.0- Methanol 45.5; Acetone 45.5

After the subbing layer had dried, the usual .light-sensitive emulsion layer was coated di-' rectly on it. After exposure and processing the emulsion adhered tenaciously to the cellulose acetate-propionate film support.

Example III A film base prepared from a poly (vinyl chloride-vinyl acetate) was coated with the followin subbing composition:

light-sensitive emulsion layer was coated dlrectly on it. After exposure and processing the emulsion adhered tenaciou-sly to the synthetic linear superpolymer film support.

The photographic film bases produced according to the present invention were found to be entirely satisfactory and to give the customary physical requirements, such as, extreme strength, flexibility, and good water-resistance.

The small quantity of the mixture of formamide and glycerol-a-chlorohydrin, which may remain with the gelatin after evaporation of the solvent or solvent mixture from the subbing composition, has no adverse efiect upon the light-sensitive emulsion layer nor has the subbing composition any adverse effect upon the container in which it is stored, or upon the coating equipment employed.

It will be understood that wherein the claims appended hereto the term subbing is used, that such is intended to include the operation of dispersing a subbing layer from any one of the subbing compositions prepared in accordance with the present invention.

I claim:

1. A gelatin composition suitable for the subbing of a photographic film support, which comprises from 0.5% to 1.5% of gelatin dispersed in an organic solventfor said support by means of from 5 to 20% of,,.a mixture of formamide and glycerol-achlorohydrin in the ratio ranging from 1:1 to 1:2 respectively.

2. A gelatin composition suitable for the subbing of a cellulose acetate photographic film support which comprises from 0.5% to 1.5% gelatin dispersed in a mixture of methanol and acetone, by means of from 5 to 20% of a mixture of formamide and glycerol-a-chlorohydrin in the ratio ranging from 1:1 to 1:2 respectively.

3. A gelatin composition suitable for the subbing of a photographic film support which consists of the following constituents:

Parts by weight Gelatin 1.0 Formamide 5.0 Glycerol-a-chlorohydrin 10.0 Methanol 42.0

Acetone 42.0

4. A gelatin composition suitable for the subbing of a photographic film support which consists of the following constituents:

Parts by weight Gelatin 1.0 Formamide 4.0 Glycerol-a-chlorohydrin 4.0 Methanol 45.5 Acetone 45.5

5. A gelatin composition suitable for the subbing of a photographic film support which consists of the following constituents:

The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,341,377 Middleton et a1. Feb. 15, 1944 2,313,570

Nadeau et al Mar. 9, 1943 

